Looks, to be the vacuum hose; from your fuel pressure regulator to the intake manifold. You can get vacuum hose; that will work at any auto parts store (the "regular" rubber style hose; tends to get brittle and hard, prematurely from the extreme heat of the engine compartment, however). If you want the stock, braided version (last longer; less affected by the heat); I would go by your local Volkswagen dealer with your VIN # and your parts dept. should be able to provide the hose you need.