Ah, I understand you.
It is possible - but not elegant. DVD drives are much bigger than standard hard drives - so you would need to a buy a 5.25in type external SATA enclosure and a 5.25in to 3.5in mounting adapter to attach the HDD into the much larger enclosure. However, due to the placing of the fixed SATA ports in the enclosures, this may require some SATA data and power extension cables to correctly connect up the hard disk, which may be fiddly to connect.
Such a system would require you to disassemble the enclosure every time you want to swap between the two drives. Instead I would suggest you just buy two separate SATA enclosures: one 5.25in, one 3.5in.