user: Question: What is the entry for weight in kilograms of jockey D. Nikolic?
Columns: ['Result', 'Date', 'Race', 'Venue', 'Group', 'Distance', 'Weight (kg)', 'Time', 'Jockey', 'Winner/2nd']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['4th', '19 Aug 2007', '3yo Maiden', 'Sale', 'NA', '1208m', '57.0', '1:12.89', 'L. Nolen', '1st - Aceland Street']
SQL:

assistant: SELECT "Weight (kg)" FROM "Table" WHERE "Jockey" = 'D. Nikolic';