Which Jewish leader

Question: 

Which top Jewish leader visited Jesus at night?

Wooden statue of Nicodemus carved by Giovanni Angelo Del Maino, ca. 1518
Answer: 

Nicodemus.  You can read about it in John 3:1-12 where Jesus completely confuses poor Nicodemus by telling him he has to be born again.

You can learn more about Nicodemus here.

You can read a sermon by Anne Robertson about what it means to be "born again".

Above is a wooden statue of Nicodemus carved by Giovanni Angelo Del Maino, ca. 1518