Thanks topsquark for passing by. I am talking about a physical pendulum and I know that

T = 2π√[ I / mgh ]

I think that the pivot will be at the end of the uniform cord, therefore its moment of inertia, I, is (1/3)mL^2

is it correct to add the moment of inertia like this?

T = 2π√[ mL^2 / 3mgh ]

since h = L

T = 2π√[ L / 3g ]

If this is correct, how to add the mass M of the bob?