Question:
Which position did Donald Anderson, Baron Anderson of Swansea hold in Mar, 1990?

Context:
 Donald Anderson, Baron Anderson of Swansea holds the position of Member of the 48th Parliament of the United Kingdom from May, 1979 to May, 1983. 
 Donald Anderson, Baron Anderson of Swansea holds the position of Representative of the Parliamentary Assembly of the Council of Europe from Nov, 2015 to Nov, 2017. 
 Donald Anderson, Baron Anderson of Swansea holds the position of Member of the 47th Parliament of the United Kingdom from Oct, 1974 to Apr, 1979. 
 Donald Anderson, Baron Anderson of Swansea holds the position of Member of the 49th Parliament of the United Kingdom from Jun, 1983 to May, 1987. 
 Donald Anderson, Baron Anderson of Swansea holds the position of Member of the 50th Parliament of the United Kingdom from Jun, 1987 to Mar, 1992. 
 Donald Anderson, Baron Anderson of Swansea holds the position of Member of the 51st Parliament of the United Kingdom from Apr, 1992 to Apr, 1997. 
 Donald Anderson, Baron Anderson of Swansea holds the position of Member of the 44th Parliament of the United Kingdom from Mar, 1966 to May, 1970. 
 Donald Anderson, Baron Anderson of Swansea holds the position of Member of the 52nd Parliament of the United Kingdom from May, 1997 to May, 2001. 
 Donald Anderson, Baron Anderson of Swansea holds the position of Member of the House of Lords from Jun, 2005 to Dec, 2022. 
 Donald Anderson, Baron Anderson of Swansea holds the position of Member of the 53rd Parliament of the United Kingdom from Jun, 2001 to Apr, 2005.

Answer:
Member of the 50th Parliament of the United Kingdom