Partial correlation with a zero link

Let $(X_1, X_2, X_3)^T$ have the following distribution $N_3 \left(\begin{pmatrix} 0 \ 0 \ 0 \end{pmatrix}, \begin{pmatrix} 1 & 0.4 & 0 \ 0.4 & 1 & 0.6 \ 0 & 0.6 & 1 \end{pmatrix}\right)$. Then the value of the partial correlation coefficient between $X_1$ and $X_2$ given $X_3$ is __________ (rounded off to two decimal places).