user: Question: What was the host for the semi final heat, when Terry Wogan was the National Final main host, and Gaby Roslin was the National Final co-host?
Columns: ['Year(s)', 'Selection show', 'Venue', 'National final main host', 'National final co host', 'Semi final/heat host']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1956', 'UK did not participate', 'UK did not participate', 'UK did not participate', 'UK did not participate', 'UK did not participate']
SQL:

assistant: SELECT "Semi final/heat host" FROM "Table" WHERE "National final main host" = 'Terry Wogan' AND "National final co host" = 'Gaby Roslin';