What is the boy sitting on?
The boy is sitting on the bench.
    src        edge_attr  dst
0     0               of    6
1     0  to the right of    8
2     1               of    9
3     1  to the right of    6
4     1  to the right of    5
5     5  to the right of    7
6     5   to the left of    1
7     5  to the right of   11
8     6   to the left of    1
9     6       sitting on    9
10    6          wearing   11
11    7               of    6
12    7   to the left of    5
13    8               of    6
14    8   to the left of    0
15    9               in    4
16    9               of    3
17    9      in front of   12
18   10               of    6
19   11   to the left of    5
20   12           behind    9