Democrat in a hole in the time before Christmas (6)
I believe the answer is:
advent
'the time before christmas' is the definition.
(advent is the period leading up to Christmas Day)
'democrat in a hole' is the wordplay.
'democrat' becomes 'd'.
'in' means one lot of letters goes inside another.
'hole' becomes 'vent' (vent is a kind of hole).
'a'+'vent'='avent'
'd' placed into 'avent' is 'ADVENT'.
'in' acts as a link.
(Other definitions for advent that I've seen before include "Forty days preceding Christmas" , "Second Coming" , "Season for a candle?" , "Period before Christmas" , "Arrival of important person or event" .)