Result is Leo leaving South Pole, devastated (6)
I believe the answer is:
upshot
'result' is the definition.
('upshot' can be a synonym of 'result')
'leo leaving south pole devastated' is the wordplay.
'leaving' suggests deleting specific letters.
'devastated' indicates an anagram (devastate literally means destroy or lay waste to).
'south'+'pole'='southpole'
'southpole' with 'leo' taken out is 'suthpo'.
'suthpo' with letters rearranged gives 'UPSHOT'.
'is' acts as a link.
(Other definitions for upshot that I've seen before include "Outcome, consequence" , "Event" , "increased exposure" , "issue" , "anti-aircraft fire?" .)