How do I create and render a custom region?
I got the solution and so sharing with all, if it could help someone:

Creating a custom region in our theme if we are using display suite module is slightly different.

1.First define region in your theme's .info file (same as we do without display suite)

regions[name_of_region] = 'Name of Region' 


2.Then print the following line in your template file wherever you want to display

print render(block_get_blocks_by_region('name_of_region'));