Admissions to any universities or colleges are given based on your rank. Based on your overall percentile your rank could be between 521730 - 586500 approximately. As you mentioned you come from SC category, it would be little difficult for you to get into NIT's and IIT's.

However you could predict the colleges you are eligible for using the below link.

https://engineering.careers360.com/jee-main-college-predictor?utm_source=qna&utm_medium=jee_cp

Dear Aspirant !

Hope you are doing well ! It is not a good score and you will not get any better college at this percentile. Work harder in next upcoming April attempt of jee mains.With 49 percentile, you have failed to qualify JEE main and thus you are not eligible for JEE advanced examination.

Hope it helps you

Thank you