user: Question: Who has a walking data of 214.061km?
Columns: ['Event', 'Data', 'Athlete', 'Date', 'Place']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['1500 m', '5:46.24', 'Roger Mills', '29 August 1975', 'London , United Kingdom']
SQL:

assistant: SELECT "Athlete" FROM "Table" WHERE "Data" = '214.061km';