<sup>17</sup>O NMR study of the local charge state in the hole-doped Cu<inf>2</inf>O<inf>3</inf> two-leg spin-ladder A<inf>14</inf>Cu<inf>24</inf>O<inf>41</inf> (A<inf>14</inf>=La<inf>6</inf>Ca<inf>8</inf>, Sr<inf>14</inf>, Sr<inf>11</inf>Ca<inf>3</inf>, Sr<inf>6</inf>Ca<inf>8</inf>)