Maybe first or second row in exam (7)
I believe the answer is:
ordinal
'maybe first' is the definition.
('first' is an ordinal number)
'second row in exam' is the wordplay.
'second row' becomes 'din' (both can mean a loud disturbance. I am not sure about the 'second' bit.).
'in' is an insertion indicator.
'exam' becomes 'oral' (spoken academic test).
'din' put into 'oral' is 'ORDINAL'.
'or' acts as a link.
Can you help me to learn more?
(Other definitions for ordinal that I've seen before include "Ninth, maybe" , "First, for One" , "Number defining a thing's position in series" , "Indicating position in sequence - iron lad (anag)" , "Numerals such as first and second" .)