Why is the following function not o(h)?

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Given that a function is $o(h)$ if

\begin{equation} \lim_{h \to 0} \frac{f(h)}{h}=0\\ \end{equation}

Why is $P(N(h)>0) \neq o(h)$ (where $N(h)$ is a Poisson process) ?

My attempt

\begin{equation} P(N(h)>(k=0)) = 1-P(N(h)=0) = 1 - \frac {e^{-\lambda h}(\lambda h)^k}{k!}\\ \end{equation}

which gives \begin{equation} P(N(h)>(k=0)) = 1 - \frac {e^{-\lambda h}(1)}{1}\\ \end{equation}

and then dividing by h,

\begin{equation} P(N(h)>(k=0)) = \frac {1 -e^{-\lambda h}}{h}\\ \end{equation}

If I were to take $\lim_{h \to 0}$, wouldn't the numerator essentially be $1-1=0$? How should I approach this?