To use `Labeled` to make the kind of label you want, you have to wrap a specific point with `Labeled`. You also have to use `Rotate` to get the rotation.

Here is the code:

    data = Table[{x, x^2}, {x, 0, 10, 0.1}];
    data[[61]] = Labeled[data[[61]], Rotate[Style[x^2, 14, Bold], 40 °]];
    ListLinePlot[data]

`data[[61]]` is the point `{6., 36.}`

[![plot][1]][1]


  [1]: https://i.sstatic.net/7g8QZ.png