There hereby is created a Pittock Mansion Advisory Commission for the City, to which the Mayor, Commissioner In Charge of the Bureau of Parks, and Superintendent of Parks shall be ex officio members. The Commission shall otherwise consist of nine members appointed by the Mayor. The Mayor shall initially appoint two members for 1 year, three members for 2 years, two members for 3 years, and two members for 4 years. Thereafter all appointments shall be by the Mayor for 4-year terms, provided, when an interim vacancy occurs the appointment shall be to fill the unexpired term of the position vacated. All members shall serve without compensation. The term of each such appointment shall be extended as necessary so that the term ends November 1.