Ohio law requires financial responsibility in the minimum amount of $12,500 for bodily injury to or death of one (1) individual in any one (1) accident, $25,000 for bodily injury to or death of two (2) or more individuals in any one (1) accident, and $7,500 for injury to the property of others in any one (1) accident. This being if you are driving the car.
If you want to garage the car you can drop down to comprehensive only. You can still keep the plates on and you have to have it registered regardless. But if you drive that car out of the garage with comp only you are driving uninsured. The only way around this is to purchase an umbrella policy with extra liability coverage over all your existing policies (auto, fire home, whatever).