In some cases, that's because a candidate is running unopposed. In others, it's because only two candidates are running, and they're both from the same party.
But the really interesting races to watch are the ones in which the race for 2nd place is too close to call and the outcome could cement that seat for one party in the general. Here are a few such races to keep an eye on in the State Assembly.
District numbers are followed by the cities with the largest population contained within, in full or in part. (Results were as of just after midnight. Check out our live results page for the latest updates.)
District 1 - Redding, Susanville, Truckee
Two Republicans lead this one. Candidate Brian Dahle has a comfortable lead with 34%. In second place, for now, is Rick Bosetti, but he only enjoys a 2% lead over Democrat Robert Meacher as of the time of writing. That could turn this into a mixed race for November. No incumbents in the First District, and about half of precincts have reported so far.
District 3 - Chico, Yuba City, Paradise
This one's not as close, but if 3rd place candidate Bob Williams makes up a few thousand votes to pass Democrat Charles Rouse, it will be an all Republican race in November. Incumbent Dan Logue (R) has a solid lead.
District 6 - Roseville, Folsom, Rocklin
With only a quarter of the precincts reporting so far and only a few percentage points between each candidate, this race could be close. Incumbent Beth Gaines (R) leads, with Democrat Regy Bronner in a fairly close second.
District 10 - Santa Rosa, Petaluma, San Rafael
Two Democrats are in the lead, but there's about a 4% difference between each of the top three. Incumbent Michael Allen (D) probably feels pretty good right now, but if Democrat Marc Levine slides a few points back, it will be a Republican and a Democrat in November.
District 23 - Fresno, Clovis
This one currently looks to be an all-Republican race for November, but in reality the second place spot is up for grabs. There's no incumbent, and Richard Rojas (D) is barely a percentage point behind Republican Bob Whalen, as the count nears a close (80% of precincts are reporting).
District 25 - San Jose, Santa Clara, Fremont
It's a mixed race now, but 2nd place candidate Arlyne Diamond (R) enjoys just a 1% margin over Democrat Pete "Primo" McHugh. If McHugh moves up, it will be a Dems only party in November. Incumbent Bob Wieckowski(D) has a solid lead.
District 36 - Lancaster, Palmdale, California City
Two Republicans are at the top with about a third of precincts reporting. Barely a third of a percent is keeping Dem Steve Fox from making it to the General Election right now. There is no incumbent.
District 46 - Los Angeles
It's a Democrat-Republican race for now, with only 11% reporting. Republican Jay Stern is in 2nd place with 21.2%. Brian Johnson (D) was coming in at 17.3%. With a bump, Johnson could turn this into a Dem-Dem race in November. There is no incumbent.
District 47 - Fontana, Rialto, San Bernardino
Two Dems have the lead, but this race is just starting. Joe Baca Jr. has a secure lead with 40%, but Democrat Cheryl Brown has only a 5% lead over Republican Jeane Ensley with just 2% of precincts reporting. There is no incumbent.
District 50 - Los Angeles, Santa Monica, West Hollywood
Extremely tight race, with only 1% between each of the top three. Bradly Torgan, the only Republican in the race against 3 Democrats, has 2nd place with 26.6% for now. Betsy Butler (D) is the incumbent and for now is not one of the top two, though only 15% of precincts are reporting.
District 72 - Garden Grove, Huntington Beach, Westminster
This is another very close race for 2nd. Joe Dovinh (D) is holding on for now against Long Pham and Travis Allen, both Republicans. There is no incumbent and Troy Edgar (R) has a fairly solid lead overall.