what is the SNDR of non linear response
SNDR is the ration between the power of the signal and the power of
the noise

No, it's the ratio of the signal to the noise-plus-distortion. A very similar term is SINAD i.e. total signal in noise and distortion and, it amounts to largely the same thing.

in the Vout we will have harmonics of f,3f,DC which of them i consider
noise?

Well, none of them really. Noise is only really relevant if it's problematic and DC cannot really be regarded as problematic unless your signal is a DC signal. So your output, in the absence of any other information is: -

DC (unwanted)
f (the wanted signal)
3f (unwanted distortion)
noise (zero)