Answer:
3, 4, 7, 9, 10, 11, 13
Explanation:
The block in the bottom right would be in the bottom corner of the grid. This makes it block #13.
The block above this one would be block #9. This section has 3 blocks horizontally in a row; this makes it take up block #10 and block #11 as well.
There are two blocks above block #11; this makes it block #7 and block #3.
There is one block to the right of block #3; this makes it block #4.