Mount a donkey in auditorium for finale (6)

I believe the answer is:

ascend

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'mount' is the definition.
(I've seen this in another clue)

'a donkey in auditorium for finale' is the wordplay.
'donkey in auditorium for' becomes 'sc' (I can't explain this - if you can you should believe this answer much more).
'finale' becomes 'end' (the end of a story or show).
'a'+'sc'+'end'='ASCEND'

Can you help me to learn more?

(Other definitions for ascend that I've seen before include "shift to a higher plane" , "Scale" , "Get higher" , "Mount" , "Gain height" .)

I've seen this clue in The Irish Times.

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