Oil separator hose

I have a 1978 308 GTS USA carburetor car. I need to replace the hose that comes from the bottom of the oil separator to the sump. My hose got "cooked" and cracked where it passed under the rear exhaust header. It looks like a 10mm inner diameter hose.

I run 10% ethanol gasoline. What is the best hose for this application and what is the exact size?

Thanks in advance.