I have been attempting with a simple listing enter the following data:

A1
a1 32
A1 53

Changing cell C1 from A1 to a1 I should get either 32 or 53.

=INDEX(B1:B5,MIN(IF(EXACT(C1,A1:A5)=FALSE,"",EXACT (C1,A1:A5)*ROW(INDIRECT("1:"&ROWS(A1:A5))))))

returns "#VALUE!"