can not select data for my database

I AM NEW IN PHP MY QUERY IS list($title)=$db->fetch_one_row("SELECT category_name FROM ".TABLE. "WHERE 'gallery-cat-id'=$cid");

then i got erroe in

SELECT category_name FROM tbl_gallery_categoryWHERE 'gallery-cat-id'=5--You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ''gallery-cat-id'=5' at line 1

why this happen