Well-off area: right district selected originally for a Keith or Gordon? (8)
I believe the answer is:
richards
'a keith or gordon?' is the definition.
(eg Keith Richards or Gordon Richards)
'well-off area right district selected originally' is the wordplay.
'well-off' becomes 'rich' (similar in meaning).
'originally' indicates taking the first letters.
The initial letters of 'area right district selected' is 'ards'.
'rich'+'ards'='RICHARDS'
'for' is the link.
(Other definitions for richards that I've seen before include "Keith --, one of The Rolling Stones" , "Keith --, Rolling Stone" .)