The girl from number 50A (4)

I believe the answer is:

nola

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'the girl' is the definition.

'from number 50a' is the wordplay.
'from' becomes 'no' (I can't explain this - if you can you should give a lot more credence to this answer).
'number' becomes 'L' (L is an example).
'50a' becomes 'a'.
'no'+'l'+'a'='NOLA'

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