Among those who turned out to endorse Inez Dickens , a real estate developer and a daughter of Lloyd E. Dickens , an assemblyman with a long political and entrepreneurial career in Harlem , were three of the four members of the group known as the Harlem Clubhouse : former Mayor David N. Dinkins , Congressman Charles B. Rangel and Percy E. Sutton , the former Manhattan borough president and one-time mayoral candidate .