Any candidate for alderperson under the terms of this Article may appoint in writing over his signature not more than one representative for each place of voting, who shall have the right to act as challenger and watcher for such candidate at any election at which his name is being voted upon. Such challenger and watcher shall have the same powers and privileges as a challenger and watcher under the election laws of this State applicable to Chicago. No political party shall have the right to keep any challenger or watcher at any polling place at any election held under the provisions of this Article unless candidates for some office other than alderperson are to be voted for at the same time.