Section 1-204.11 - The Chairman(a) The Chairman shall be the presiding officer of the Council.(b) When the Office of Mayor is vacant, the Chairman shall act in his stead. While the Chairman is Acting Mayor he shall not exercise any of his authority as Chairman or member of the Council. Dec. 24, 1973, 87 Stat. 788, Pub. L. 93-198, title IV, § 411.