Hello student,
With a score of 540 in the exam, you have chances of procuring a seat in the following government colleges in EBC category under the state quota when comparing the results of previous years

• Nalanda medical college and hospital
• Dharbanga medical college
• Indira Gandhi institute of medical sciences

Also, one thing to keep in mind is that scores and ranks vary each year with difficulty level of the question paper and availability of seats and state quotas. However you can go through the following link to know about the cut off's and ranks for the previous years and calculate your chances of selection
https://medicine.careers360.com/articles/neet-cutoff-bihar
Good luck