Write SQL query to solve given problem: How many turnovers per game did the assist champion had in the 2003 NBA season?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT AVG(T2.turnovers) FROM players AS T1 INNER JOIN players_teams AS T2 ON T1.playerID = T2.playerID WHERE T2.year = 2003 GROUP BY T1.playerID, T2.assists ORDER BY T2.assists DESC LIMIT 1