You are qualified for SSC CGL, yes.
Your eligibility is unaffected by your 12th grade grades or subject-specific results; SSC CGL only requires that you hold a **bachelor's degree from an accredited university**.
There is no issue because you meet the graduation requirements and your 12th grade report indicates that you passed.

Additionally, your 12th grade percentage of 54% is irrelevant for CGL.
Just make sure that you have graduated or plan to graduate before the deadline indicated in the notification.