Sana, while filling the application form, please mention that you are appearing for the qualification examination. In the application form, there is a question:

Are you appearing for Graduation Degree Examination through Regular Mode/Distance Mode or Open Mode. Select "Yes" and then the mode through which you are appearing for the exam. In that case, it will not ask you for your Graduation marks. But if it still does, mention your previous semester marks. For more information as to how to fill in the Application form, please read the FAQs at the official website: https://view.mahacet.org/mahacet/admin/news_document/TipsforFillingMAH-LL.B-3YearCET2020form.pdf