How to write Select statement for this codition

I need to check whether SGTXT contains BELNR value.

SGTXT is a text field and It should be matched with BELNR

How to write select statement for this.

Select AUGBL AUGDT into t_BSAD

from BSAD

where SGTXT should have the given BELNR Value.

Plz note : Here I cannot give as SGTXT = BELNR as coz BELNR have only 10 digits.