HANA Instr function to check for numbers?

Hi,

I am trying to create a calculated column to check the validity of another field for the presence of numbers in the string.

For example

Partner     Tel_number     Valid

1               1flowers          Yes

2               Telephone       No 

3               6046060543    Yes

My Expected result would be for partner 1 and 2 to return valid results and partner 2 to be invalid.

What is the correct syntax for instr to do this?

I've already tried the following:

IF(INSTR("TEL_NUMBER",IN(0,1,2,3,4,5,6,7,8,9)),0,1)

IF(INSTR("TEL_NUMBER",'1' OR '2' ...... ),0,1)

Thanks!

John