Create a table in SQLite database in an Android app

I'm trying to create a simple Contacts application where I use SQLite DB.

I created to make my own DBHelper class:

public class DBHelper {
public static final String KEY_NAME = "name";
public static final String KEY_ADDRESS = "address";
public static final String KEY_MOBILE = "mobile";
public static final String KEY_HOME = "home";
public static final String KEY_ROW_ID = "_id";
public static final String PROJECTION[] = {
        KEY_ROW_ID,
        KEY_NAME,
        KEY_ADDRESS,
        KEY_MOBILE,
        KEY_HOME
};
/* The table and database names */
private static final String TABLE_NAME = "mycontacts";
private static final String DATABASE_NAME = "contactDB";

    /*SQL code for creating the table*/

private static final String TABLE_CREATE=
        "create table "+ TABLE_NAME + "("+ KEY_ROW_ID
                +" integer primary key autoincrement,"+
                KEY_NAME +" text not null,"+
                KEY_ADDRESS + " text not null,"+
                KEY_MOBILE + " text,"+
                KEY_HOME + " text)";

private static final int DATABASE_VERSION = 1;

private SQLiteDatabase db;

public DBHelper(Context ctx){
    db = ctx.openOrCreateDatabase(DATABASE_NAME, SQLiteDatabase.CREATE_IF_NECESSARY, null);
    db.execSQL(TABLE_CREATE);
}
...
`enter code here`}

In the constructor of the class, as you can see, I create/open the db, after which I make CREATE_TABLE query to it in order to create mycontacts table.

When I run the app (on Android Studio's emulator) I get the following runtime error:

Caused by: android.database.sqlite.SQLiteException: table mycontacts already exists (code 1): , while compiling: create table mycontacts(_id integer primary key autoincrement,name text not null,address text not null,mobile text,home text)

It says that the table has already been created, despite the fact that I put the creation query right after the db's creation. How is that possible?