District housing new stadium (5)
I believe the answer is:
arena
'stadium' is the definition.
('arena' can be a synonym of 'stadium')
'district housing new' is the wordplay.
'district' becomes 'area' (I've seen this before).
'housing' indicates putting letters inside.
'new' becomes 'n'.
'area' placed around 'n' is 'ARENA'.
(Other definitions for arena that I've seen before include "Ring for contest" , "O2, for example" , "Sphere of intense activity" , "Part of a stadium" , "Place or scene of activity" .)