Ohio Rev. Code § 727.38
If an assessment proves insufficient to pay the cost of a public improvement, the legislative authority of a municipal corporation may levy an additional assessment to supply the deficiency. Such additional assessment shall be levied against the same properties as were assessed for the cost of the improvement and shall be assessed among such properties in the same proportion as the assessment for the cost of the improvement was levied. Such additional assessment shall be subject to the same limitations as the assessment for the cost of the improvement. In case a larger amount is collected from an assessment than is necessary to pay the cost of the improvement or to retire the bonds or notes issued in anticipation thereof, the amount of such assessments collected in excess of that necessary to pay such costs or retire such bonds or notes shall be returned to the persons from whom it was collected in proportion to the amounts collected from each such person respectively.
R.C. §727.38