  In the $B^+\to D^+ D^-K^+$ decay, LHCb has reported the observation of the
open-charm exotic states $X_{0,1}^0\equiv X_{0,1}(2900)^0$ with four different
quark flavors $(\bar c d \bar su)$, where the subscripts (0,1) denote the
spins. To confirm the discovery, we propose $\Lambda_b\to \Sigma_c^{0(++)}
X_{0,1}^{\prime\,0(--)}$ in the final state interaction, where
$X_{0,1}^{\prime\,0(--)}$ with $\bar c s u\bar d$ ($\bar c s d\bar u$) are the
new $X_{0,1}$-like exotic states. More specifically, $\Lambda_c^+D_s^-$ in
$\Lambda_b\to \Lambda_c^+D_s^-$ are transformed as $\Sigma_c^{0(++)}
X_{0,1}^{\prime\,0(--)}$, by exchanging $\pi^{+(-)}$. Particularly, we
calculate ${\cal B}(\Lambda_b\to \Sigma_c^{0(++)} X_{0,1}^{\prime\,0(--)})
=(2.3\pm 0.6,4.3^{+3.3}_{-2.5})\times 10^{-4}$, and estimate other $b$-baryon
decays with the $X_{0,1}$-like states, such as ${\cal B}(\Xi_{b}^{0(-)}\to
\Xi_{c}^{0(+)}(2645)X_{0}^{\prime\,0(--)}, \Lambda_{b}\to
\Xi_{c}^{\prime\,0}X_{0,1}^{0})\sim 10^{-5}$. One needs $\Lambda_b\to
\Sigma_c^{0(++)}M_c M$ to observe $X_{0,1}^{\prime\,0(--)}\to M_c M$ with $M_c
M=D_s^-\pi^+$, $\bar D^0 \bar K^0$ $(D_s^-\pi^-$, $D^-K^-)$. We find that
$\Lambda_b\to \Sigma_c^{0(++)} M_c M$ avoids the resonant charmonium decays,
which have caused a difficult amplitude analysis in $B^+\to D^+ D^-K^+$.
Therefore, $\Lambda_b\to \Sigma_c^{0(++)}
X_{0,1}^{\prime\,0(--)},X_{0,1}^{\prime\,0(--)}\to M_cM$ can be large and
clean, promising to be observed by the near future measurements.
