If at the time of annulment there are any pending actions or proceedings by or against the town, or if after the effective date of annulment an action or proceeding out of a cause of action which arose prior to the time of annulment, which but for the annulment would have been by or against the town, is instituted, the county or counties in which the town was located shall be substituted in place thereof and the proceeding may be perfected to judgment. The agreement required by § 15.2-3701 may provide that if judgment against the county or counties results from the proceeding, the liability shall be paid by the special debt district as provided in § 15.2-3709.