Partisan assembly produces a candidate (8)
I believe the answer is:
aspirant
'a candidate' is the definition.
(I've seen this before)
'partisan assembly' is the wordplay.
'assembly' is an anagram indicator.
'partisan' with letters rearranged gives 'ASPIRANT'.
'produces' is the link.
(Other definitions for aspirant that I've seen before include "expressing high ambition?" , "One works hard to achieve something" , "Partisan sort of hopeful" , "pretender" , "Candidate; one with a desire to succeed" .)