Kentuckiana is something most Kentuckians I know have heard of before. If there's one for Ohio, I haven't heard it. Well at least not an endearing one. FIFO - Fucking Idiot From Ohio - is maybe just as well known as Kentuckiana, though! :P
Also, not that it gets me hot under the collar or anything but it seems like you're genuinely misinformed so I'll point it out to you, it's totally inaccurate to say "half" of Kentucky is centered around Cincinatti. 25% of Kentucky lives literally in Louisville or Lexington. After that you have about 3 of the top 10 counties by population that are close to Cincy (Kenton, Boone, and Campbell). Quite a stretch from "half" of the state lol.
Kentuckiana is one I've always heard, but kind of figured it was only the northwestern part. I live like 5 minutes away from Indiana.