I can offer a practical scenario to help you decide which version to use.

You phone your sister, who is coming to the party where you are now, to ask her to bring your phone, which you left at home accidentally. You have borrowed a friend's phone to make the call.

Sis: Who is this?

You: It's me. I forgot my phone. I am using Mary's. Can you please bring it with you?

Sis: Where is it?

You: It is in my room on the table.

If there is only one table in your room, the above is good. She will know to look on the table in your room.

But what if it is in your dresser, which has two small half-height and half-width drawers on top, and full-height and full-width drawers below them. You cannot remember which little drawer you put your phone in:

You: It is in the dresser, in a little drawer.

I can offer a practical scenario to help you decide which version to use.

You phone your sister, who will be coming to the party where you are now, to ask her to bring your phone, which you left at home accidentally. You have borrowed a friend's phone to make the call.

Sis: Who is this?

You: It's me. I forgot my phone. I am using Mary's. Can you please bring it with you?

Sis: Where is it?

You: It is in my room on the table.

If there is only one table in your room, the above is good. She will know to look on the table in your room.

But what if it is in your dresser, which has two small half-height and half-width drawers on top, and full-height and full-width drawers below them. You cannot remember which little drawer you put your phone in:

You: It is in the dresser, in a little drawer.

She will know to look in the other little drawer if the phone is not in the first little drawer she opens.

That is just one example. We would need a thousand more examples to cover all of the remaining situations.