Let $A$  and  $B$  be any two points on y-axis and the line  $y=2x$ respectively. Also $P$  and $Q$   be the feet of perpendicular from $A$  and $B$  on the line $y=2x$  and y-axis respectively. If $AB$  passes through the points  $(1,3),$ then the line $PQ$  passes through fixed point $(x_1,y_1)$  such that $\frac{y_1}{x_1}$  is