Dette burde virke:
DELETE Y
FROM YourTable Y JOIN
(
SELECT
name, cl_1, cl_2, cl_3, cl_4, cl_5, cl_6
FROM YourTable
GROUP BY name, cl_1, cl_2, cl_3, cl_4, cl_5, cl_6
HAVING COUNT(1) > 1
) T ON Y.name = T.name
AND Y.cl_1 = T.cl_1
AND Y.cl_2 = T.cl_2
AND Y.cl_3 = T.cl_3
AND Y.cl_4 = T.cl_4
AND Y.cl_5 = T.cl_5
AND Y.cl_6 = T.cl_6
BTW -- Hvad med række 3 og 6? De ser ud til at være nøjagtig de samme?
http://sqlfiddle.com/#!2/26b8b/1