The spirit of March and November (5)
I believe the answer is:
demon
'the spirit' is the definition.
(demon is a kind of spirit)
'march and november' is the wordplay.
'march' becomes 'demo' (I've seen this before).
'and' is a charade indicator (letters next to each other).
'november' becomes 'n' (phonetic alphabet: alpha, bravo, charlie etc.).
'demo'+'n'='DEMON'
'of' acts as a link.
(Other definitions for demon that I've seen before include "ace" , "beast" , "malignant spirit" , "Skilful person" , "Evil spirit, devil" .)