user: Question: What is the name of the 1st Party that has a 3rd Party of Unionist, and 2nd Member of Sir John Boyd-Orr?
Columns: ['Election', '1st Member', '1st Party', '2nd Member', '2nd Party', '3rd Member', '3rd Party']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1918', 'Sir William Cheyne', 'Coalition Conservative', 'Dugald McCoig Cowan', 'Coalition Liberal', 'Sir Henry Craik', 'Coalition Conservative']
SQL:

assistant: SELECT "1st Party" FROM "Table" WHERE "3rd Party" = 'Unionist' AND "2nd Member" = 'Sir John Boyd-Orr';