A historic, 1940s-era Dupont Circle building is the latest D.C. office property to be pitched for a residential conversion. A rendering of an apartment conversion at Dupont Circle’s Longfellow Building at 1201 Connecticut Ave. NW. Rockville-based Duball filed plans Wednesday with the Historic Preservation Office to turn 1201 Connecticut Ave. NW, also known as the Longfellow Building, into 161 apartments and ground-floor retail….
