Hello Sunita
As we know, Joint Entrance Exam or JEE Main is the national level undergraduate engineering entrance exam which is gateway for the admission to various B.Tech/B.E. programmes offered by 31 NITs, 23 IIITs and 23 CFTIs.
Recent changes in JEE Main 2019 allows candidates to appear twice for the entrance exam in a given year. The best result of the two exams is taken to consideration.
Now, regarding eligibility, there are certain eligible criteria prescribed by the JEE authorities, which are mentioned below:

• Age: candidates need to pass 10+2, and no age limit.
• Educational qualification: the candidate must have scored the minimum of 75% marks or should be in the top 20 percentile of their respective boards. For candidates belonging to SC/ST category minimum scores required is 65%.
• Subjects: the candidate must be student with Mathematics, Physics, Chemistry/Biology/Biotechnology/Technical Vocational Subject, Language and any other subject is eligible.

As you can see, there's no specific mention about supplementary board exam results being not taken to consideration. As long as you are a passed 12th graduate with minimum 75% (65% if you're not general category), you're eligible candidate to appear for the examination.

Long story short: Yes, you can appear for JEE main if you clear the reexamination with minimum of 75%.

Now that you're eligible to appear for exam itself, what's stopping you from getting in IIT itself? The result you secure in JEE main, and if you clear the cut off (based on your category), JEE advance which has only the following rule:

• Candidates seeking admission to the architecture course must have passed 10+2 or equivalent examination with 50% marks in Physics, Chemistry and Mathematics and also 50% marks in aggregate in the qualifying examination. No Diploma holder is eligible for the entrance exam.

Only the rank you secure here will tell whether or not you'll manage to get admission in one of the most prestigious institutions of the country; reexamination or not, board result is a board result.

Best of luck!