@nadeshseen First of all, It is not accurate to say TLB stores bits required to address main memory, it stores the page table of a process and relevant page table entry in page table says where the part of the process is stored in main memory. Now coming back to your query, since a process size or logical address space could be more than main memory size then some part of the process would be stored in secondary memory, now if we have to execute the part of the process which is not in main memory, then how would we do that?
If we call address in the form of physical address space to fulfil our need, we can never reach to the code which is in secondary memory but if we call it in the form of virtual memory(logical address space) then we can fetch that part of the process also and control unit of CPU replaces the required pages with earlier pages present in the main memory.