Constitution of the State of Ohio Art. IV, § 15

Laws may be passed to increase or diminish the number of judges of the supreme court, to increase beyond one or diminish to one the number of judges of the court of common pleas in any county, and to establish other courts, whenever two-thirds of the members elected to each house shall concur therein;  but no such change, addition or diminution shall vacate the office of any judge;  and any existing court heretofore created by law shall continue in existence until otherwise provided.