Ohio Rev. Code Ann. § 153.52

A contract for general contracting or for doing the work belonging to each separate branch or class of work specified in division (B) of section 153.50 of the Revised Code, or for the furnishing of materials therefor, shall be awarded by the public authority referred to in section 153.50 of the Revised Code, in its discretion, to the lowest responsive and responsible separate bidder therefor, in accordance with section 9.312 of the Revised Code in the case of any public authority of the state or any public institution belonging thereto, and to the lowest and best separate bidder in the case of a county, township, or municipal corporation, or any public institution belonging thereto, and to the lowest responsive and responsible bidder in the case of a school district, and shall be made directly with the bidder in the manner and upon the terms, conditions, and limitations as to giving bond or bid guaranties as prescribed by law.