user: Question: What is the dissolved date of the parliament assembled on 4 November 1461 with an unknown 2nd member?
Columns: ['Summoned', 'Elected', 'Assembled', 'Dissolved', '1st member', '2nd member']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['23 May 1461', '1461', '4 November 1461', '6 May 1462', 'unknown', 'unknown']
SQL:

assistant: SELECT "Dissolved" FROM "Table" WHERE "2nd member" = 'unknown' AND "Assembled" = '4 November 1461';