<Tr> <Th_colspan="2"> Leadership </Th> </Tr> <Tr> <Th> President of the Senate & Vice President </Th> <Td> Mike Pence (R) Since January 20, 2017 </Td> </Tr> <Tr> <Th> Speaker of the House of Representatives </Th> <Td> Paul Ryan (R) Since October 29, 2015 </Td> </Tr> <Tr> <Th> President pro tempore of the Senate </Th> <Td> Orrin Hatch (R) Since January 6, 2015 </Td> </Tr>

What is congress and what does it do