  We report a comprehensive $^{139}$La and $^{63}$Cu nuclear magnetic resonance
study on La$_{2-x}$Sr$_x$CuO$_4$ ($0.07\leq x \leq 0.2$) single crystals. The
$^{139}$La spin-lattice relaxation rate $^{139}T_1^{-1}$ is drastically
influenced by Sr doping $x$ at low temperatures. A detailed field dependence of
$^{139}T_1^{-1}$ at $x=1/8$ suggests that charge ordering induces the critical
slowing down of spin fluctuations toward glassy spin order and competes with
superconductivity. On the other hand, the $^{63}$Cu relaxation rate
$^{63}T_1^{-1}$ is well described by a Curie-Weiss law at high temperatures,
yielding the Curie-Weiss temperature $\Theta$ as a function of doping. $\Theta$
changes sharply through a critical hole concentration $x_c\sim 0.09$. $x_c$
appears to correspond to the delocalization limit of doped holes, above which
the bulk nature of superconductivity is established.
