Congress is the Legislative branch of government that consists of the House of Representatives and the Senate.
The President is in the Executive Branch
The Democrats currently have control of the Senate and the Republicans control the House of Representatives.
However, the Democrats don't have a super majority in the Senate, so the Republicans can stop any legislation requiring a 60 vote majority. Since the Republicans control the House, no legislation can pass unless the Democrats can muster enough Republican votes to get their legislation to the Senate.