Any way you define “suspense,” the word doesn’t apply to Ohio’s November election, at least as to General Assembly and congressional contests. Districts drawn by Republicans favor Republicans, and so the legislature will continue to be Republican-run, and even though Ohio twice voted for Barack Obama, most of Ohio’s U.S. House members will be Republican. Yes, history proves that Ohio Democrats, when they could, drew tilted districts, though that was a while ago. Yes also, when Democrats last ran the Ohio House, they cold-shouldered a reasonable plan to at least try to make Ohio General Assembly and congressional districts less one-sided. Drawing tilted maps is called “gerrymandering,” named for a Massachusetts governor, Gerry (rhymes with “Gary”), who signed a slanted remap in the Bay State in 1812. So, if Democrats somehow run the Ohio General Assembly in 2021, after 2020’s census, they’ll draw Ohio’s congressional districts to suit Democrats. If Republicans run things, they’ll do the same for the GOP.
As for General Assembly districts, whichever party wins two of these three offices in 2018 (governor; state auditor; secretary of state) will draw General Assembly districts in 2021 to favor that party. Those officeholders form the kernel of the state Apportionment Board, which draws General Assembly districts.
Republicans used the Apportionment Board to draw GOP-leaning General Assembly districts in the mid-1960s, and in 1991, 2001 and 2011. Democrats did that, too, in 1971 and 1981, to give their party an edge in the legislature.
The system isn’t a slam-dunk. The state Senate see-sawed between the parties in the mid- to late 1970s and early ‘80s, but Republicans won the Senate in November 1984 and have held it ever since. As for Ohio’s House, Democrats ran it for 22 years, from November 1972 to November 1994. Republicans have ruled the roost for 17 of the 19 years since.