user: Question: What is Winner, when Prize is "£50,000", and when Runner-Up is "Korosh Nejad"?
Columns: ['Season', 'Winner', 'Prize', 'Runner-Up', '3rd place']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['1', 'Dave Ulliott', '£40,000', 'Peter Evans', 'Dave Welch']
SQL:

assistant: SELECT "Winner" FROM "Table" WHERE "Prize" = '£50,000' AND "Runner-Up" = 'Korosh Nejad';