Car a Duke included in list (8)
I believe the answer is:
roadster
'car' is the definition.
(roadster is a kind of car)
'a duke included in list' is the wordplay.
'duke' becomes 'd'.
'included in' is an insertion indicator.
'list' becomes 'roster' (roster is a kind of list**).
'a'+'d'='ad'
'ad' placed into 'roster' is 'ROADSTER'.
(Other definitions for roadster that I've seen before include "Old car" , "Open two-seater car" , "sporty vehicle" , "Small open-top car" , "An open car without rear seats" .)