30 day notice to vacate

[Christy Porter]

we had a tenant move out. They called and said they were planning to move out but could not give a timeframe. They were informed during the call they must give a 30 day notice. 1 week later, we went to the apartments and found there apartment vacate, they left. ( our lease does not state they need to give 30 day notice, "new leases will have it" but Ohio Law B) Except as provided in division (C) of this section, the landlord or the tenant may terminate or fail to renew a month-to-month tenancy by notice given the other at least thirty days prior to the periodic rental date. 

Our question is, since our lease did not state, 30 day notice, but state laws says they need to give , can we enfore the 30 day notice with them.