I suppose you're referring to the 20th Amendment to the Constitution of the United States?
If so, I don't see how there could be much of any value to this name.
For anyone that isn't familiar with the Twentieth Amendment to the Constitution they can find a summary of it at:
Also, if you're from another country, you probably have no clue, whatsoever, what this domain name refers to (20th Amendment to what?!?).
Maybe you could get $5-$10 for it.
Good luck though,