Hook to be used when creating a database table

As mentioned, after_switch_theme should be a pretty good choice. Your table create/update function will only run when you switch themes, which should be roughly like activating a plugin. If you use dbDelta to create and/or update the table there should be no issue with table creation. From the Codex:

global $wpdb;
$installed_ver = get_option( "jal_db_version" );

    if( $installed_ver != $jal_db_version ) {

      $sql = "CREATE TABLE $table_name (
         id mediumint(9) NOT NULL AUTO_INCREMENT,
         time datetime DEFAULT '0000-00-00 00:00:00' NOT NULL,
         name tinytext NOT NULL,
         text text NOT NULL,
         url VARCHAR(100) DEFAULT '' NOT NULL,
         UNIQUE KEY id (id)
      );";

      require_once( ABSPATH . 'wp-admin/includes/upgrade.php' );
      dbDelta( $sql );

      update_option( "jal_db_version", $jal_db_version );
    }

That will check the hard-coded table version against the version stored in the database and create or update if necessary. Note: it will create or update based on calculations made by dbDelta. It will not try to create the same table twice. If the table already exists it will try to apply the differences between the existing table and the new table definition.