Hi Mithun,
If your customer is having SAP Customer OnDemand 1305, you are perfectly fine with the SAP Solutions OnDemand studio 1305.
Please note that the name of the studio changed over time. In the beginning, SAP Business ByDesign gave its name to the studio. You will only need the SAP Business ByDesign studio today if your customer is still on SAP Business ByDesign FP 4.0.
Later on, the studio name changed because the studioo could also be used to enhance other SAP cloud solutions, for example SAP Customer OnDemand (and SAP Business ByDesign as of 1302!). It was then renamed to SAP Solutions OnDemand Studio and covers the versions 1302 and 1305.
As of version 1308, the studio will again change its name to reflect the name change of the cloud solutions, for exampe, SAP Cloud for Customer. The new name of the studio is SAP Cloud Applications studio.
I hope this answers your question.
Best regards
Ulrike
SAP Cloud Knowledge Management