What Size Hose for Portable A/c. Dehumidifer?

So I have a portable a/c and I need to use the Dehumidifer function, but I don't have a hose. I can't figure out what size hose I need, I don't know why .. I keep starting at this tape and converting to cm to inch to fraction an I'm going crazy.

What size ID / OD Hose would properly fit this? The black one is the cap that closes the drain pipe. The White one is the drain pipe I need a hose to fit over.

(I tried looking in the manual and website, and I emailed their customer support but they didn't get back to me. It's really basic, but my heads not working right now and I don't can't make multiple trips to the store-.-)

Okay, so I figured I needed a 19/32" OR 0.59375" ID.

My options at the store were:
9/16" (0.5625")
5/8" (0.625")

So I went with the 5/8" (0.625") option, and tightened it down with a clamp. That weird A/c drain hole is made on a slight slant so it was difficult to get the clamp to stay tightly, wanted to keep slipping off.

Hopefully that stays and is nice and tight, I will check back in an hour.