This is bit of sledgehammer approach which works with your data. If your data always starts with 0 then below formula can be reduced.
=MID(A3,MIN(SEARCH({0,1,2,3,4,5,6,7,8,9},A3&"0123456789",1)),FIND("_",A3,MIN(SEARCH({0,1,2,3,4,5,6,7,8,9},A3&"0123456789",1)))-MIN(SEARCH({0,1,2,3,4,5,6,7,8,9},A3&"0123456789",1)))