Procession Democrat organised about first of October (9)
I believe the answer is:
motorcade
'procession' is the definition.
(motorcade is a kind of procession)
'democrat organised about first of october' is the wordplay.
'organised' indicates an anagram.
'about' is an insertion indicator.
'first of' says to take the initial letters.
The first letter of 'october' is 'o'.
'democrat' is an anagram of 'motrcade'.
'motrcade' placed around 'o' is 'MOTORCADE'.
(Other definitions for motorcade that I've seen before include "vehicles in procession" , "Convoy" , "Procession using cars" , "Procession of cars bringing VIP" , "Moving display" .)