user: Question: When Johannesburg is the hometown who is the contestant?
Columns: ['Country', 'Contestant', 'Age', 'Height (cm)', 'Height (ft)', 'Hometown']
Types: ['text', 'text', 'real', 'real', 'text', 'text']
Sample row: ['Argentina', 'María Mercedes Viaña', 19.0, 174.0, '5\'8.5"', 'Santiago del Estero']
SQL:

assistant: SELECT "Contestant" FROM "Table" WHERE "Hometown" = 'Johannesburg';