\definereferenceformat[eqref][left=(,right=)]

\starttext
\placeformula[(N)]
\startformula
	\Pr\{N = n\} = \Pr\left\{ \min_{1 ≤ k ≤ n} S_k > 0 \right\} = p_n^{(1)}
\stopformula

Is it working? \eqref[(N)]

\CONTEXT\ \contextmark\ \contextversion
\stoptext