The record is held by District of Columbia (4)
I believe the answer is:
disc
'the record' is the definition.
('disc' can be a synonym of 'record')
'is held by district of columbia' is the wordplay.
'held by' is an insertion indicator.
'district of columbia' becomes 'dc' ('DC' can be a synonym of 'district of columbia').
'is' going within 'dc' is 'DISC'.
(Other definitions for disc that I've seen before include "Capital of India" , "Flat, circular plate - record" , "Back part" , "Sound recording" , "Flat thin circular body" .)