Match with interval
Solution 1:
Use a formula like below:
=INDEX($A$1:$C$1,MATCH(165,INDEX((--LEFT($A$2:$C$2,FIND("-",$A$2:$C$2)-1)),)))
With your local settings, change the , to ;:
=INDEX($A$1:$C$1;MATCH(165;INDEX((--LEFT($A$2:$C$2;FIND("-";$A$2:$C$2)-1));)))
The inner INDEX returns an array of the first numbers: 1,20,150. The Match then returns where the value 165 lands in that array and returns the relative column number to the INDEX.