Present state supporting old refuge (5)
I believe the answer is:
oasis
'refuge' is the definition.
(I know that oasis is a type of harbor)
'present state supporting old' is the wordplay.
'present state' becomes 'asis' (as things currently are).
'supporting' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'old' becomes 'o' (abbreviation as in OT - Old Testament).
'asis' put after 'o' is 'OASIS'.
(Other definitions for oasis that I've seen before include "place of relief" , "quiet spot" , "Fertile part of desert" , "English rock group in the desert" , "Pop group" .)