PG diploma in Management in Operational Research is suitable for distance learning or Executive MBAs as I am a working professional.
Which course to go depends on your current working profile. If you're already in operations department and want to upgrade, then PGDM in OPS can be beneficial but if you want to learn the managerial skill of all the domains like finance, marketing, operations, HR etc, the An executive course will be beneficial as it will have physcical occasional classes which wiull enhance your learning.