user: Question: What is Silver, when Notes is "6.24km, 23controls"?
Columns: ['Year', 'Gold', 'Silver', 'Bronze', 'Notes']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [2002.0, 'Michael Mamleev', 'Yuri Omeltchenko', 'Jamie Stevenson', '5.2km, 15controls']
SQL:

assistant: SELECT "Silver" FROM "Table" WHERE "Notes" = '6.24km, 23controls';