How to select columns which have NULL Values in table

Question

I Have Below table with name tbl_custmaster

 

custno	name	col1	col2	col3	cul4
1	A	NULL	NULL	2	NULL
2	B	1	2	NULL	2
3	C	1	NULL	NULL	NULL
4	D	NULL	NULL	NULL	NULL

 

want to show only those column whose have null values.

 

ex.- select * from  tbl_custmaster where custno=1

then required  below output.

 

col1	col2	cul4
NULL	NULL	NULL