Ban a panto that's distressed the leader (3,6)
I believe the answer is:
top banana
'leader' is the definition.
(informal term for a leader or important person)
'ban a panto that's distressed' is the wordplay.
'that's distressed' indicates an anagram.
'ban'+'a'+'panto'='banapanto'
'banapanto' is an anagram of 'TOP BANANA'.
'the' acts as a link.
(Other definitions for top banana that I've seen before include "Most important person in group (informal)" , "Best of the bunch!" , "organisation chief" , "first on hand?" , "figurehead?" .)