2 alternatives in attached file. An array formula (no helper columns), or with an helper column to concatenate L&M columns.
EDIT: Bosco's comment was not visible when I posted. It sure is more elegant. Can't get it into my head to use index within a match
my third alternative would have been,
=IFERROR(INDEX($N$3:$N$709,AGGREGATE(15,6,ROW($N$3:$N$709)/(($L$3:$L$709&$M$3:$M$709)=(A3&B3)),1)),"Not Found")