Raspberry Pi Python - Water Level Indicator

I have a Raspberry Pi that is connected to the breadboard. I'm using a BC548 NPN transistor. I want to know what will I code if the wire(color green) touches the water and the LED will turn on. Below also is my sample code and the comment explains all.

I'm using flask to have a web server. This is my code:

import RPi.GPIO as GIO
from flast import Flask

GPIO.setmode(GPIO.BOARD)
GPIO.setup(12,GPIO.OUT)
GPIO.output(12,GPOO.LOW)     //resets the led

app = Flast(__name__)
@app.route('/')
def index():
    return 'Hello'
    // i want to add code if(wire touches the water) then led will turn on and print('wire touches water')

if __name__ == '__mnain__':
    app.run(debug=True, host='0.0.0.0')

GPIO.cleanup()

I want to add something like if (wire touches water) then GPIO.output(12, 1) and print('wire touches water'). How can I do this?

Sorry I'm new to the Python language same as the Raspberry Pi. doing this for my project. My main language is Java. But I can learn the syntax of it. Thank you.