<Tr> <Td> </Td> <Td> Henry A. Wallace </Td> <Td> January 20, 1941--January 20, 1945 </Td> <Td> President of the Senate </Td> </Tr> <Tr> <Td> </Td> <Td> Harry S. Truman </Td> <Td> January 20--April 12, 1945 </Td> <Td> President of the Senate </Td> </Tr> <Tr> <Td> </Td> <Td> Kenneth McKellar </Td> <Td> April 12, 1945--January 4, 1947 </Td> <Td> President pro tempore </Td> </Tr> <Tr> <Td> </Td> <Td> Arthur H. Vandenberg </Td> <Td> January 4, 1947--January 3, 1949 </Td> <Td> President pro tempore </Td> </Tr>

Who is the presiding officer of the house of representatives and the senate