What does 'Describe the language of this automaton' mean?
The language of an automaton is the language accepted by the automaton, that is, the set of words accepted by the automaton.
Now, certainly, one way of describing the language is as the language accepted by this particular automaton. But the question is asking you to find a simpler description. Here is the set of words accepted by your automaton:
$$
01, \\
001, 101, \\
0001, 0101, 1001, 1101, \\
00001, 00101, 01001, 01101, 10001, 10101, 11001, 11101, \\
\ldots
$$
Can you spot a pattern?