The President of Council shall act as presiding officer of the Council in the absence or disability of the Mayor and shall exercise all the powers and duties granted the Mayor by this Charter during the absence or disability of the Mayor. While presiding over special or regular meetings of the Council, the President of Council may vote upon all matters coming before the Council, but in no event shall the President of Council, in such persona dual capacity as Council member and presiding officer of Council, cast more then one vote on any action. In the event that the office of Mayor shall become vacant, the President of Council shall become Mayor for the unexpired term, and the Council shall elect a successor from among the membership of the Council to the office of President of Council for that unexpired term.