Capital piece of terra cotta wanted (6)
I believe the answer is:
ottawa
'capital' is the definition.
(capital of Canada)
'piece of terra cotta wanted' is the wordplay.
'piece of' says the answer is hidden in the clue.
'OTTAWA' is hidden in the letters of 'terra cotta wanted'.
(Other definitions for ottawa that I've seen before include "N. American city" , "Canada's capital" , "somewhere in Canada" , "Foreign capital" , "North American city" .)