Reserve national team for national leader (6)
I believe the answer is:
walesa
'national leader' is the definition.
(I know that Walesa is a national leader)
'reserve national team' is the wordplay.
I cannot really see how this works, but
'team' could be 'wales' (I have seen 'International team' mean 'wales' so perhaps 'team' could also mean 'wales') and 'wales' is found within the answer.
A single letter 'a' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'for' is the link.
Can you help me to learn more?
(Another definition for walesa that I've seen is " Lech - - , ex Polish president".)