Can't execute query

SELECT `product_id` FROM `products_default` WHERE `designtype`='' AND `season`='winter' AND `skill_`='1' GROUP BY `product_id` 

MySQL Error: Unknown column 'skill_' in 'where clause' in /var/www/vhosts/with-compliments.nl/httpdocs/lib/functions.php on line 548

This script cannot continue, terminating.