City crest, one Lee devised (9)
I believe the answer is:
leicester
'city' is the definition.
(Leicester is an example)
'crest one lee devised' is the wordplay.
'one' becomes 'i' (Roman numeral).
'devised' indicates an anagram.
'crest'+'i'+'lee'='crestilee'
'crestilee' anagrammed gives 'LEICESTER'.
(Other definitions for leicester that I've seen before include "Elizabeth the first's favourite" , "Orange kind of cheese" , "Sheep - cheese" , "City, Robert Dudley" , "royal favourite" .)