Write SQL query to solve given problem: What is the ratio between the number of object samples in image 1 and the number of object samples in image 6?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(SUM(CASE WHEN IMG_ID = 1 THEN 1 ELSE 0 END) AS REAL) / SUM(CASE WHEN IMG_ID = 6 THEN 1 ELSE 0 END) FROM IMG_OBJ