According to David Oxenford’s Broadcast Law Blog, FCC political rules apply to off-year elections for vacant congressional, state and local offices. Broadcast stations serving districts with special federal/congressional elections need to offer candidates reasonable access, lowest unit rates and equal opportunities. In states where there are no special congressional elections, there are other political races taking place in this off-year and most of the political rules apply to these state and local electoral races as well.
Candidates for state and local elections are entitled to virtually all of the political broadcasting rights of Federal candidates – with one exception, the right of reasonable access, which is reserved solely for Federal candidates. That means that only Federal candidates have the right to demand access to all classes and dayparts of advertising time that a broadcast station has to sell. For state and local candidates, on the other hand, stations don’t need to sell the candidates any advertising time at all. But, if they do, the other political rules apply.