Dem
51
GOP
49
Ohio law states that parties must file the names of their candidates 90 days before the election. This year that is Aug. 7. However, the Democratic National Convention doesn't begin until Aug. 19, so Joe Biden can't be the official nominee until then at the earliest. This situation happens all the time for the party with the August convention, but normally the state legislature grants that party a waiver.
This year, however, the Republicans are playing hardball and want to keep Biden off the ballot. Ohio AG Dave Yost (R) said that provisional approval is not allowed, nor does Secretary of State Frank LaRose (R) have the authority to do anything about this. An attorney on Yost's staff, Julie Pfeiffer, said: "No alternative process is permitted."
This is where the parties differ. The Republicans will use every trick in the book to pick up votes by suddenly enforcing a long-dormant rule or changing the rules during the campaign season, as they tried (and failed) in Nebraska, where they tried to make the state winner-take-all. Democrats don't do that, which puts them at a disadvantage.
Biden will probably lose Ohio even if he is on the ballot, but his absence could hurt Sen. Sherrod Brown (D-OH), and this is probably what the Republicans are gunning for: to defeat Brown. It is virtually certain that Democrats will sue Ohio. They will make the case that Ohio didn't seem to have a problem in 2020 putting Donald Trump on the ballot, even though he didn't formally accept the nomination until Aug. 27, 2020. We don't know what the Ohio Supreme Court will do when/if it gets the case, but Yost is going to have to explain why the law can be violated when it is a Republican who is threatened with being left off the ballot but not when it is a Democrat. (V)