how to figure out that it contains 13 and 15 ?
You can go with either one.
SELECT * FROM table WHERE string LIKE '%13%
SELECT * FROM table WHERE string REGEXP '.*13.*'
Then just do
AND string REGEXP '.*15.*'
As for using LIKE, I know its slower then other things, but barely if not useable in mySQL? I've been using it for a while with no notable issues.