Hey Avinav! With 20 marks out of 200 in WBJEE , you can expect a rank  between 10,900 and 11,300 .And considering this to be your general rank , you have chances for govt., semi government or private colleges which include following colleges at the top :

• University of kalyani
• Haldia institute of technology
• Heritage institute of technology
• University of burdwan

And many more.

You can check the list of all possible colleges by going through the following link:

https://www.careers360.com/wbjee-college-predictor

Hope it helps!