Outcome of Ulster riot (6)
I believe the answer is:
result
'outcome' is the definition.
(I know that outcome can be written as result)
'ulster riot' is the wordplay.
'riot' indicates an anagram.
'ulster' anagrammed gives 'RESULT'.
'of' acts as a link.
(Other definitions for result that I've seen before include "Final score" , "'Outcome, upshot (6)'" , "Outcome of an undertaking" , "End - issue" , "Effect of lustre" .)