Oracle’s place, quiet in Asian metropolis (6)
I believe the answer is:
delphi
'oracle's place' is the definition.
(location of ancient Greek oracle)
'quiet in asian metropolis' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano').
'in' is an insertion indicator.
'asian metropolis' becomes 'delhi' (**).
'p' inserted inside 'delhi' is 'DELPHI'.
(Other definitions for delphi that I've seen before include "Ancient Greek sanctuary dedicated to Apollo" , "Old Greek city" , "Greek site of Apollo's most famous oracle" , "Scene of Greek oracle" , "Where Apollo's most famous oracle spoke in Greece" .)