Yea you can without a permit but there's no laws in Ohio protecting you while open carrying from harrassment, the minute someone calls the police and says there's someone carrying a gun you will be arrested for "inciting a panic" was what my cousin in mansfield Ohio was told
This is why I won't OC in OH. The laws in OH basically allow them to arrest you for doing something completely legal. I know to many people that live in OH and heard way to many stories of un-informed cops that don't know it's legal or don't want it to be legal to even mess with it.