Answer
$y=\dfrac{1}{3}$
Work Step by Step
Using $y=mx+b$ where $m$ is the slope and $b$ is the $y$-intercept, then the equation of the line with the given slope equal to $
0
$ and the given $y-$intercept equal to $\left(0,
\dfrac{1}{3}
\right)$, is
\begin{array}{l}
y=0x+\dfrac{1}{3}
\\\\
y=\dfrac{1}{3}
.\end{array}