Find all Duplicates from a Table In Sql Server

I have a table which contains two columns of Urls and it contains duplicates.I'm looping through each row but have no idea to check duplicates.I want to send oldurl as parameter to check duplicates and get them.Can anyone help me

OldUrl     NewUrl    
---------------------
Google     Google.in
Amazon     Amazon.in
300r       300r/en-us
300r       300r/en-us