Possible leak in brake vacuum hose

Hey,

I've been learning recently to do a little work on my 2007 1.9 astra. I've noticed that there's a hissing coming from this area of the engine when I put my head near it, and if I press (not enough to deform the material) on the moulded part of the pipe the hissing stops. It looks to me like the line has previously become un-clipped from it's clip above and perhaps melted on the pipe below and someone has tried to patch it up in some way. Since it's related to the brake system, I guess ideally I should replace this section of line with a new one, but not sure what I need to be looking for on google/asking from the dealer to get this part. Searching for variations on brake vacuum hose didn't turn up anything that looked like a really close match, but maybe the dealer will just know what I mean by that? Or am I just over-thinking this, and the pump is able to pull enough of a vacuum even with a small leak in the pipe (I would assume there'd be a code or something if it wasn't?) - didn't want to take any chances with the braking system though :D

Thanks,
Marcus