Question:
Which position did Jo Grimond hold in Nov, 1956?

Context:
 Jo Grimond holds the position of Member of the 48th Parliament of the United Kingdom from May, 1979 to May, 1983. 
 Jo Grimond holds the position of Member of the 45th Parliament of the United Kingdom from Jun, 1970 to Feb, 1974. 
 Jo Grimond holds the position of Member of the 44th Parliament of the United Kingdom from Mar, 1966 to May, 1970. 
 Jo Grimond holds the position of Member of the 43rd Parliament of the United Kingdom from Oct, 1964 to Mar, 1966. 
 Jo Grimond holds the position of Member of the House of Lords from Oct, 1983 to Oct, 1993. 
 Jo Grimond holds the position of Member of the 39th Parliament of the United Kingdom from Feb, 1950 to Oct, 1951. 
 Jo Grimond holds the position of Member of the 42nd Parliament of the United Kingdom from Oct, 1959 to Sep, 1964. 
 Jo Grimond holds the position of leader of the Liberal Party from Nov, 1956 to Jan, 1967. 
 Jo Grimond holds the position of Member of the 41st Parliament of the United Kingdom from May, 1955 to Sep, 1959. 
 Jo Grimond holds the position of Member of the 40th Parliament of the United Kingdom from Oct, 1951 to May, 1955. 
 Jo Grimond holds the position of Member of the 47th Parliament of the United Kingdom from Oct, 1974 to Apr, 1979. 
 Jo Grimond holds the position of Member of the 46th Parliament of the United Kingdom from Feb, 1974 to Sep, 1974.

Answer:
Member of the 41st Parliament of the United Kingdom