On an 'Open' work permit what NOC code should I say for the EE?

[Sighman]

Hi,

I have an open work permit but work in NOC code 7313 (and have Canadian RED SEAL qualification)
There is no option of saying open in the question about what NOC is on your work permit.
I put 7313 otherwise I can't complete the form........

What have others done?

Thanks!