The rank of 50 marks will be under of 165679 – 120612 . IIT Delhi has release the cutoff for JEE advanced 2020 in the brochure.
This year the jee advanced paper was total of 396 marks.
As per the cut off of 2020 for JEE advanced, if you belong from OBC category then you must have to score at least 31.5% aggregate of the total marks.
That means, as you belong from OBC category then you have to score 31.5 % of 396 marks to qualify in JEE advanced. Now as you are getting 50 marks in OBC category then you have not qualified the cutoff marks and so you cannot get any IIT.

As you have given JEE mains then you can check out our JEE mains college predictor tool to get an appropriate idea of the colleges that you can get on the basis of your JEE mains rank :-

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

Also if you want to try our JEE advanced college predictor tool then you can use this tool to predict your colleges that you can get on the basis of your score. the link is :-

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

Hey aspirant,

I hope you are doing well.

The JEE reservation criteria is provided to candidates belonging  to categories of GEN-EWS(15%), OBC-NCL(27%), SC(15%), ST(7.5%) and Person With Disabilities (PWD)(5% in each category). Candidates who are appearing or are going to appear in the upcoming session of JEE should know how understanding the reservation norms is beneficial in terms of comparatively lower application fee, cutoff marks, and also the course/ admission fee payable at the time of admission in the respective institute. There are institutes that follow the reservation criteria while there are others that follow the home state quota and other state quota.

There are different factors upon which the selection and cutoff depends and these factors are different for different programs and different institutes. These factors include the difficulty level of the examination, number of aspirants, category under with admission is desired, and home state of the candidates.

Since,  you haven't mentioned your home state so I couldn't predict which college he can get. But, below is the link to our college predictor tool which may be helpful

I hope it helps.

Best of Luck!