That depends on whether you want the points from both the Bachelor degree and the 10+2 degree counted for Express Entry or only one of them. I suggest you try to estimate the points you would earn for each degree using http://www.cic.gc.ca/english/immigrate/skilled/eca-conversion.asp Then you can make a decision based on how many CRS points you have overall (without the ECA's), how many points each ECA would get you, and how many points you probably need to get the Invitation to Apply. For the latter, you can check the previous Rounds of Invitations:
It also depends on which program you want to apply for. For the Federal Skilled Workers program, for example, you must get an ECA for at least one of your degrees. But for the Canadian Experience Class, you don't necessarily need any ECA (if you have enough points otherwise).
In any case, if you decide you want to get an ECA for both degrees, then you need to get them separately. You cannot combine two degrees in one ECA. You must get a separate ECA for each degree.