hi,

no march session is separate and since you have separately registered for march session, correction of form would only considered for march session exam. jan 27 - 31 for jee mains 2021which was for february session exam.  however iat the time of form filling it is not necessary to have the category certificate, students may fill the self declare form and upload the certificate with in end of may, 2021, upon failing to upload the category certificate , your candidature would be cancelled. so in case you do not fall in any category it is best to apply as general candidate.

hope it would help.

you may use careers360 jee main college predictor tool to know about possible college name based on your score and category:

https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer