Filing of affidavit. The City Council may issue a subpoena for the attendance of witnesses or the production of other evidence at a hearing upon the request of a member of the City Council or upon the written demand of any party. The issuance and service of such subpoena shall be obtained upon the filing of an affidavit therefor which states the name and address of the proposed witness; specifies the exact things sought to be produced and the materiality thereof in detail to the issues involved; and states that the witness has the desired things in the witness's possession or under the witness's control. A subpoena need not be issued when the affidavit is defective in any particular.