Just the one academic doing for English or American writer (6)
I believe the answer is:
london
'american writer' is the definition.
(novelist Jack London)
'just the one academic doing for english' is the wordplay.
I cannot quite see how this works, but
'one' could be 'o' (I've seen this in other clues) and 'o' is present in the answer.
'academic' could be 'don' (type of academic - especially at Oxbridge) and 'don' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'or' acts as a link.
Can you help me to learn more?
(Other definitions for london that I've seen before include "England's capital city" , "English capital" , "- Clay; - pride; - plane" , "British capital" , "City for the odd non-old" .)