Making a login page

[card51shor]

Hey guys I'm working on a log in page and I'm getting an error that it's a tuple value but I am just trying to get one value. Does anyone see the error in my code?
Thanks!

import os
import psycopg2


from flask import Flask, session, render_template, request
from flask_session import Session
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker


app = Flask(__name__)

# Check for environment variable
if not os.getenv("DATABASE_URL"):
    raise RuntimeError("DATABASE_URL is not set")

DATABASE_URL = os.environ['DATABASE_URL']
conn = psycopg2.connect(DATABASE_URL, sslmode='require')

# Configure session to use filesystem
app.config["SESSION_PERMANENT"] = False
app.config["SESSION_TYPE"] = "filesystem"
Session(app)

# Set up database
engine = create_engine(os.getenv("DATABASE_URL"))
db = scoped_session(sessionmaker(bind=engine))


@app.route("/welcome")
def index():
    return render_template("welcome.html")

@app.route("/login")
def login():
    password = request.form.get("password")
    username = request.form.get("username")
    db.execute('SELECT * FROM users WHERE username = %s AND password = %s', (username, password,))
    account = db.fetchone()
    if account:
        return render_template("login.html")
    else:
        print "No!"

@app.route("/home")
def home():   
    return render_template("home.html")




            
          
@app.route("/register", methods=["GET", "POST"])
def register():
    
    if request.method == "GET":
        return render_template("register.html")
    elif request.method == "POST":
        password = request.form.get("password")
        username = request.form.get("username")
        session.clear()
        db.execute("INSERT INTO users (username, password) VALUES (:username, :password)", {"username":username, "password":password})
        db.commit()
        return render_template("login.html")