There are a couple of different hose types for the tank to pump hose. One type has a screw on connection on one end, with a plain clamped hose end on the other, if I remember correctly. Some members have just removed the old hose from the screw connector and just use plain hose. So, depending on what you want to do, you may need to order the original part, or you can just get some hose. I believe the hose on my car ('69 280 SL) is 12 mm, or 1/2 inch will do. While you're at it, you might as well replace the return line hose, too; that one is 8 mm or 5/16.
George Davis
'69 280 SL Euro manual