<Table> <Tr> <Td> <P> Franklin Delano Roosevelt Longest presidency 4,422 days 1933--1945 </P> </Td> <Td> </Td> <Td> William Henry Harrison Shortest presidency 31 days 1841 </Td> </Tr> </Table> <Tr> <Td> <P> Franklin Delano Roosevelt Longest presidency 4,422 days 1933--1945 </P> </Td> <Td> </Td> <Td> William Henry Harrison Shortest presidency 31 days 1841 </Td> </Tr>

Who was the longest serving president in the united states
find me the text answering this question