Some companies I have managed for have had a policy whereby the associate (non-exempt) is required to be paid for a minimum of three hours if called in to cover a shift or to attend a mandatory meeting. For example if an associate has to come in for a 1 hour meeting on their day off, should they be paid for three??? Is there any Ohio or Federal law that requires such a thing???

Only a few states have a "reporting time pay" requirement, and Ohio is not one of them. Neither does federal law.