It is difficult to find these parts as, for W113, they are not on drawings in the EPC, you need to look for them in the parts list.
Ok, trying to sort it out:
1. The hose no. 6 on the drawing is
PN A113 831 09 94 (HOSE 360 MM FEED LINE FROM ENGINE TO HEAT EXCHANGER) for chassis: As of ident. no.: 044 017154
001; Up to ident. no.: 044 017199; As of ident. no.: 044 017200 SEE ENGINE PARTS LIST. Note says: order by meter, but I would check it as I recall this is a formed hose (I bought it a couple of years ago), so I do not fully trust this note.
PN A 113 831 08 94 (HOSE 360 MM FEED LINE FROM ENGINE TO HEAT EXCHANGER) for chassis: Up to ident. no.: 044 017153. Note says: order by the meter.
But it is all for W113. I would not go there.
2. For VIN 108 018 12 065696
PN A108 831 01 85 (HOSE) Note: 018 FROM CHASSIS 035637-057019; 019 FROM CHASSIS 057020 SEE GROUP 20
So we go to group 20, which is in engine, for 130980 engine. And we see:
PN A 108 831 04 94 Note: As of engine: 980 10/50,20/60 019028 980 12/52,22/62 043329 - you need to check your engine number, but I guess this is the part you need. Available at Mercedes, about $70.
This is the part I would put my money on (with all the appropriate disclaimers).
Please note that for W108 you may find Niemoeller more useful than SLS-HH shop. Although drawings are less friendly than in the SLS.
The straight connector appeared in the engine block: As of engine: 980 10/50,20/60 014829 980 12/52,22/62 030432 981 10/50,20/60 000341 981 12/52,22/62 002211 983 10/50,20/60 005302 983 12/52,22/62 008785 984 10/50,20/60 000339 984 12/52,22/62 000140,
where 10 is manual, 12 automatic. It looks some engines left factory with straight connector and old hose type... just my supposition.
If your engine number is different and does not fit for the part number I put in bold above (it is below 19028 for manual or 43329 for automatic), you will need the part numbers I listed in point 2 above.