Couple of the French get nothing (3)
I believe the answer is:
'couple' is the definition.
'of the french get nothing' is the wordplay.
'of the french' becomes 'du' ('of the' in French).
'get' says to put letters next to each other.
'nothing' becomes 'O' (looks like zero - 0).
(Other definitions for duo that I've seen before include "They might play" , "Two-person act" , "Performing pair" , "Brace" , "Two of a kind" .)